Add support for async mode and use es2020 version for parsing Javascript

• chore(deps): bump highlight.js from 10.3.2 to 10.5.0 (#6) 8d8c860
• feat: add support for optional chaining 23d0aab
• refactor: use ecmaVersion 2020 to use latest node features 23e5a3e
• refactor: expose async mode as a property on the parser 8af8cfb
• chore: update dependencies 6e138c4
• chore(deps): bump ini from 1.3.5 to 1.3.7 (#5) 8fc0010

v6.0.1...v6.0.2